Mobile computing devices have seen explosive growth over the past few years. With growing computational power and memory capacity, personal computing devices, have become essential tools of modern life, providing telephone and text communications, navigation, photo and video functionality in a package that fits in one's pocket. As a result of providing so many different types of radio frequency communications services and displaying high-quality video, many smart phones and similar mobile computing devices are now configured with a large number of programmable processors in a small footprint.
Currently, processors have become very smaller but more powerful. Many have attempted to create a smaller sized mobile phone in a watch casing or a similar small footprint. However, these attempts have been generally unsuccessful due to limitations on antenna sizes allowed by such packages. For good radio frequency reception, the length of the antenna plus the antenna ground plane should be at least one half wavelength of the RF signals being transmitted.
Generally, an antenna ground plane may require anywhere from 40 mm to 80 mm in length due to the frequency of operation. For example, for Global Positioning System (GPS) receiver antennas a quarter wavelength for the antenna ground plane is 47 mm. For personal communication systems (PCS) antennas, a quarter wavelength for the antenna ground plane can be 40 mm in length. For cellular bands, a quarter wavelength for the antenna ground plane can be 87 mm in length. Due to the small footprint of a watch casing, the wrist of the user, and the operating frequency of the antenna, a relatively larger size antenna ground plane would be required for a “watch phone” that generally is larger than the watch casing. Previous efforts to manufacture a watch phone with a smaller sized antenna ground plane have been unsuccessful.